Nubia Z18 mini Dual SIM Li3933T44P6h766343 Replacement Battery 3350mAh

Nubia Z18 mini Dual SIM / NX611J — 3.85V Li-Polymer Replacement Battery (Li3933T44P6h766343)

This 3.85V, 3350mAh (12.9Wh) lithium-polymer cell replaces the original battery in the Nubia Z18 mini Dual SIM, Z18 mini Dual SIM TD-LTE, and NX611J. It matches the OEM part number Li3933T44P6h766343 and fits the stock battery bay without modification. Dimensions are 74.52 × 61.92 × 4.36mm — verify against your current cell before installing.

• Z18 mini / NX611J platform fit: All three listed variants share the same physical footprint, connector pinout, and BMS handshake protocol. One cell covers the full model range without adapter or wiring change.
• Bench tested on actual hardware: We cycled this cell through charge and load conditions matching the Snapdragon 660 platform draw. The BMS held cutoff correctly at both the low-voltage floor and charge termination threshold — no false trips under screen-on or modem-active loads.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.

Why the Z18 mini reports wrong battery percentage after a cell swap

The NX611J uses a fuel gauge IC that builds its capacity model from accumulated charge and discharge data on the original cell. When a new cell goes in, the IC still references that old curve — so the percentage it displays does not match actual remaining charge. This shows up as the indicator jumping several percent at once or the phone hitting 0% while the cell still has usable voltage. One full discharge to auto-shutdown followed by a complete charge resets the coulomb counter and re-anchors the gauge to the new cell's real capacity.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff symptom, not a capacity fault. Under combined modem, screen, and CPU load, the cell voltage drops sharply at low state-of-charge — faster than the fuel gauge IC predicted — and the phone's protection circuit cuts power before the display percentage reaches zero. It typically resolves after two or three full discharge-charge cycles once the gauge IC recalibrates its end-of-discharge voltage model. If shutdowns persist past the third cycle, check that cell voltage at shutdown reads above 3.2V using a USB meter or diagnostics app — anything below 3.0V at cutoff points to a cell defect.